Gas burner

ABSTRACT

A gas range has a cook top and a gas burner assembly. The gas burner assembly includes a burner body positioned in the cook top and connected to a source of gas. The burner body has at least one substantially enclosed chamber. The chamber has an inner wall with at least one port, and an outer wall with at least one port. At least one gas conduit with a substantially round entry for receiving a gas flow, a throated region, and a non-round exit in flow communication with the at least one chamber.

BACKGROUND OF THE INVENTION

This invention relates generally to an apparatus for gas burners, and,more particularly, an apparatus for improved flow characteristics forgas surface burners used in a gas-cooking product.

Atmospheric gas burners are commonly used as surface units in householdgas cooking appliances. A significant factor in the performance of gasburners is their ability to withstand airflow disturbances from thesurroundings, such as room drafts, rapid movement of cabinet doors, andoven door manipulation. Manipulation of the oven door is particularlytroublesome because rapid openings and closings of the oven door oftenproduce respective under-pressure and over-pressure conditions under thecook top.

These under-pressure and over-pressure conditions cause related pressurevariations in the gas entering the burner chamber. Gas refers to any gasor fuel air mixture. The pressure variations can translate into flowdisturbances at the burner ports causing flame extinction.

Gas surface burners used in cooking products typically include a burnerbody including a plurality of burner ports through which a gas isdistributed, and a burner cap positioned over the burner body. Almostall designs include an internal chamber of increased gas volume near theburner ports. This is important where gas flow may change over time.Providing equal flame characteristics from one port to the next iscritical to prevent hot spots or uneven heating of the cooking vessels.Variations in the size of the burner port and the distance of the burnerport from the venturi can also affect the flame characteristics. Adversechanges in the flame characteristics are detrimental to variousperformance characteristics such as the inability to support flames atcertain ports particularly at very low input rates.

In these burners there are a number of port rings for the combustion ofthe gas. A typical multi-ring burner would include a doughnut shapedouter burner and a single inner burner. The outer burner would have aring of ports on the outside and inside of the burner. This would createa triple ring burner. However, these burners, while uniform in applyingheat the cooking vessel, are only efficient for large cooking vesselswhere the diameter of the vessel is larger than the burner. This isbecause there are several main factors influencing the minimum size of atriple ring burner. First, the inner burner must be sized to accommodatea stability chamber as discussed above. Second, the outer burner must beoffset from the inner burner, further, the width of the outer ring isdetermined by the size of the venturi supplying gas to the chambers ofthe outer burner. Thus the minimum diameter of the outer ring=diameterof the inner burner+2×offset from inner burner to outer burner+2×widthof the outer burner. Thus, as there is a finite distance to bemaintained between the inner and outer burners and a finite size isrequired for the inner burner, there is a need to reduce the width ofthe outer burner to decrease the size of the burner assembly.

SUMMARY OF THE INVENTION

As described herein, embodiments of the invention overcome one or moreof the above or other disadvantages known in the art.

In one aspect, a gas range has a cook top and a gas burner assembly. Thegas burner assembly includes a burner body positioned in the cook topand connected to a source of gas. The burner body has at least onesubstantially enclosed chamber. The chamber has an inner wall with atleast one port, and an outer wall with at least one port. At least onegas conduit with a substantially round entry for receiving a gas flow, athroated region, and a non-round exit in flow communication with the atleast one chamber.

In another aspect, a gas burner assembly is connected to a source ofgas. The gas burner assembly has a burner body. The burner bodycomprises at least one substantially enclosed chamber. The chamber hasan inner wall with at least one port, and an outer wall with at leastone port. At least one venturi has an input for receiving a gas flow, athroated region, and a non-round exit in flow communication with the atleast one chamber.

In yet another aspect, a gas range has a cook top; and a gas burnerassembly. The gas burner assembly includes a burner body positioned inthe cook top and connected to a source of gas. The burner body comprisesat least one chamber and at least one venturi. The chamber has an innerwall with at least one port, and an outer wall with at least one port.The at least one venturi has an input for receiving a variable gas flow,a throated region and an elliptical exit in flow communication with theat least one chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures illustrate examples of embodiments of theinvention. The figures are described in detail below.

FIG. 1 is a perspective view of a gas range according to an embodimentof the invention.

FIG. 2 is a perspective view of a burner assembly of the range of FIG. 1according to an embodiment of the invention.

FIG. 3 is a perspective view of a burner body of the burner assembly ofFIG. 2 according to an embodiment of the invention.

FIG. 4 is a top view of a burner body of the burner assembly of FIG. 2according to an embodiment of the invention.

FIG. 5 is a cutaway view of the burner body of FIG. 3 along centerline5-5.

FIG. 6 is a perspective view of multi-ring burner assembly incorporatinga burner assembly of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

While the methods and apparatus are herein described in the context of agas-fired cook top, as set forth more fully below, it is contemplatedthat the herein described method and apparatus may find utility in otherapplications, including, but not limited to, gas heater devices, gasovens, gas kilns, gas-fired meat smoker devices, and gas barbecues. Inaddition, the principles and teachings set forth herein may find equalapplicability to combustion burners for a variety of combustible fuels.The description herein below is therefore set forth only by way ofillustration rather than limitation, and is not intended to limit thepractice of the herein described methods and apparatus.

Typically, for a burner chamber, flow distribution is governed byindividual port areas. The larger ports exhibit higher flow rates thansmaller ports. Thus, port sizing, a static attribute of a burner,primarily determines this flow characteristic. This defines thedistribution of flow rates across the burner ports. In some cases, it isdesired that the flow characteristics be “dynamic” or variable. One suchinstance would be in a burner where an interior region of ports arealtered during high flow and unaltered during low flow conditions. Forexample, the inside ports are optimized for a particular flow andtherefore produce poor and undesirable operational conditions when aflow other than the optimized flow conditions are experienced.Particularly, the ports require a minimum flow rate to prevent prematureextinguishing of the cooking flame, however, due to oxygen requirementsfor proper burning, also exhibit poor performance during high flowconditions.

FIG. 1 illustrates an exemplary freestanding gas range 100 in which theherein described methods and apparatus may be practiced. Range 100includes an outer body or cabinet 112 that incorporates a generallyrectangular cook top 114. An oven, not shown in detail, is positionedbelow cook top 114 and has a front-opening access door 116. A rangebacksplash 118 extends upward of a rear edge 120 of cook top 114 andcontains various control selectors (not shown) for selecting operativefeatures of heating elements for cook top 114 and the oven. It iscontemplated that the herein described apparatus is applicable, not onlyto cook tops which form the upper portion of a range, such as range 100,but to other forms of cook tops as well, such as, but not limited to,built in cook tops that are mounted to a kitchen counter. Therefore, gasrange 100 is provided by way of illustration rather than limitation, andaccordingly there is no intention to limit application of the hereindescribed methods and apparatus to any particular appliance or cook top,such as range 100 or cook top 114.

Cook top 114 includes four gas fueled burner assemblies 200 which arepositioned in spaced apart pairs positioned adjacent each side of cooktop 114. Each pair of burner assemblies 200 is surrounded by a recessedarea 124 of cook top 114. Recessed areas 124 are positioned below anupper surface 126 of cook top 114 and serve to catch any spills fromcooking utensils (not shown in FIG. 1) being used with cook top 114.Each burner assembly 200 extends upwardly through an opening in recessedareas 124, and a grate 128 is positioned over each burner 200. Eachgrate 128 is adapted to provide the desired support of cooking vesselsand utensils over burner assemblies 200 for cooking of meal preparationsplaced therein.

FIG. 2 is a perspective view of an exemplary burner assembly 200 thatcan be used with gas range 100 (shown in FIG. 1). Burner assembly 200includes a burner cap 202 and a burner body 206. A main gas conduit 208has an orifice 212 and is open to an interior chamber or chambers ofburner body 206 and defines a passage which extends axially through thebase of burner body 206 to provide a gas or a fuel/air mixture to flowinto burner assembly 200. As used herein, the term “gas” refers to acombustible gas or gaseous fuel-air mixture.

Burner assembly 200 is mounted on a support surface, such as cook top114, of a gas-cooking appliance such as a range or a cook top 100 (seeFIG. 1). A cap 202 is disposed over the top of burner body 206. Gasenters burner body 206 at orifice 212 and traverses gas conduit 208before entering the chambers of burner body 206. Burner assembly 200also includes at least one igniter (not shown) extending through anopening in burner body 206. While one type of burner is described andillustrated, the herein described methods and apparatus are applicableto other types of burners, such as stamped aluminum burners andseparately mounted orifice burners.

Referring to FIG. 6 a multi-ring burner assembly is shown. Themulti-ring burner assembly has an inner burner assembly 300 and an outerburner assembly 200. Inner burner assembly has a single ring of portsand burner cap 302. Outer burner assembly 200 has two rings of ports.One ring of ports faces to the outside, the second ring of ports (hiddenby cap 202) faces to the inside, or toward the inner burner assembly300. Gas conduit 208 provide a supply of gas to the outer burner body206.

Now referring to FIGS. 3 and 4, FIG. 3 is a perspective view of a burnerbody 206. FIG. 4 is a top view of burner body 206 that can be used withgas range 100 (shown in FIG. 1). Burner body 206 includes at least oneconduit orifice 212 where a gas is introduced. For each orifice 212 thegas travels up gas conduit 208 to an opening 210. Each opening 210 is inflow communication with at least one chamber or set of chambers 220, 240and 260. Chambers 240 and 260 are on opposite sides of opening 210 andwill be described as separate chambers even though the chambers are notseparated by a physical obstruction and each chamber experiences similarpressure and flow of gas from opening 210.

Gas is supplied to ports 222 via chamber 220. Gas is supplied to ports262 and 264 via chamber 260. Gas is supplied to ports 242 via chamber240. Annular chamber 220 is defined by an outer wall 221, an inner wall223, a lower surface of the burner body 206, and cap 202. A plurality ofprimary burner ports 222 are disposed in outer wall 221. Primary burnerports 222 are typically, although not necessarily, evenly spaced aboutouter wall 221. Inner wall 223 forms an isolation wall between chamber220 and chamber 240. Chamber 240 is further defined by a wall 241. Aplurality of burner ports 242 are disposed in wall 241. As used herein,the term “port” refers to an aperture of any shape from which a flamemay be supported.

FIG. 5 is a cutaway view of FIG. 3. A gas conduit 208 typically has around orifice 212 where gas enters. A single jet 290 is used fordirecting a fuel into orifice 212. The jet 290 is configured smallerthen orifice 212 so atmospheric may enter between the jet 290 and thewall 213 around orifice 212. The velocity of the fuel exiting the jet290 at orifice 302 draws atmospheric air into gas conduit 208. The fueland atmospheric air compress and mix while traveling through a neckedregion 211 of the gas conduit 208. The necked region has a maximum crosssection at the orifice 212 and a minimum cross-section where transitionregion 209 begins. For optimum performance a round cross-sectionalorifice 212 is used. However, under some circumstances, a uniformlyround opening 210 is not desirable.

A uniformly round opening is not desirable where the distance betweenthe inner ring of ports 242, 262 and outer ring of ports 222 and 264 isless than the necessary diameter of the opening 210. The size of opening210 is determined by the flow rate of gas during maximum output of theburner. In these conditions it may be necessary for opening 210 to havea diameter greater then the distance between the inner and outer wall.

For example, there are situations where inadequate space is availablefor an opening 210 to have a symmetrically round cross section.Particularly, a finite distance is needed between the venturi opening210 and the ports 265 immediately radially adjacent to the opening 210.If ports 265 are too close to opening 210 much higher pressures will beexperienced at the ports. The higher pressure reduces flame stabilityand would create a hot spot under the cooking vessel. The individualsize of each of the ports 256, relative to ports further from theopening, may not be reduced either, because the reduced size ports wouldthen not support flames at anything other than maximum gas input rates.

Making the opening 210 non-round allows more space to put a baffle 270(or wall) between the opening and the ports 265 without increasing thediameter of the burner. As shown in FIGS. 3 and 4 the opening 210 isnon-round and has an elliptical shape. However, any non-round shape maybe used that is capable of supplying gas at the maximum flow rate. Thebaffle 270 redirects the flow along the baffle 270, parallel with theports 265, rather than normally into it. This way, more uniform portloading is achieved without varying the relative size of each of theports. Further, the elliptical shape of opening 210 reinforces theaction of the baffle 270, directing flow in a manner that reduces theneed to vary ports sizes to gain uniform flame lengths betweenindividual ports.

The methods and apparatus described herein facilitate providingsubstantially uniform heat distribution at relatively low input rates ina smaller diameter burner assembly.

While the invention has been described in terms of various specificembodiments, those skilled in the art will recognize that the inventioncan be practiced with modification within the spirit and scope of theclaims.

1. A gas range comprising: a cook top; and a gas burner assemblycomprising a burner body positioned in the cook top and connected to asource of gas, the burner body comprising: at least one substantiallyenclosed chamber, the chamber comprising an inner wall having at leastone port, and an outer wall having at least one port; at least one gasconduit comprising a substantially round entry for receiving a gas flow,a throated region, and a non-round exit in flow communication with theat least one chamber.
 2. The gas range of claim 1, wherein the length ofthe exit of the gas conduit is greater then the distance between theinner wall and the outer wall.
 3. The gas range of claim 1, wherein theexit of the gas conduit is elliptical.
 4. The gas range of claim 1,wherein the burner body further comprises a baffle configured betweenthe exit of the gas conduit and the outer wall.
 5. The gas range ofclaim 1, wherein the burner body comprises three substantially enclosedchambers each chamber comprising an inner wall having at least one portand an outer wall having at least one port.
 6. A gas burner assemblyconnected to a source of gas, the gas burner assembly comprising: aburner body comprising: at least one substantially enclosed chamber, thechamber comprising an inner wall having at least one port, and an outerwall having at least one port; at least one venturi comprising an inputfor receiving a gas flow, a throated region, and a non-round exit inflow communication with the at least one chamber.
 7. The gas burnerassembly of claim 6, wherein the length of the exit of the gas conduitis greater then the distance between the inner wall and the outer wall.8. The gas burner assembly of claim 6, wherein the exit of the gasconduit is elliptical.
 9. The gas burner assembly of claim 6, whereinthe burner body further comprises a baffle configured between the exitof the gas conduit and the outer wall.
 10. The gas burner assembly ofclaim 6, wherein the burner body comprises three substantially enclosedchambers each chamber comprising an inner wall having at least one portand an outer wall having at least one port.
 11. A gas range comprising:a cook top; and a gas burner assembly comprising a burner bodypositioned in the cook top and connected to a source of gas, the burnerbody comprising: at least one chamber, the chamber comprising an innerwall having at least one port, and an outer wall having at least oneport; at least one venturi comprising: an input for receiving a variablegas flow; a throated region; and an elliptical exit in flowcommunication with the at least one chamber.
 12. The gas range of claim11, wherein the burner body further comprises a baffle configuredbetween the exit of the gas conduit and the outer wall.
 13. The gasrange of claim 11, wherein the burner body comprises three substantiallyenclosed chambers each chamber comprising an inner wall having at leastone port and an outer wall having at least one port.